Heat medium soup pot over medium heat and add olive oil. When olive oil starts to sizzle, add onions to pot and sauté until onions are translucent.
Add chopped garlic and cauliflower to the pot and combine with onions. Add water to the pot, place cover and let the pot simmer for 15 minutes. When vegetables have softened, take hand held blender and puree vegetables until smooth.
Turn heat to low and stir in vegetable bouillon, butter and salt. Once butter has melted, add heavy cream or half and half and let the soup simmer for 15 minutes. Drizzle warm heavy cream, fresh cilantro leaves and chopped pistachios on top of soup and serve.